Controlling frontal photopolymerization with optical attenuation and mass diffusion.
Controlling frontal photopolymerization with optical attenuation and mass diffusion.
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DOI：
10.1103/physreve.91.062402
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发表时间：
2015-06
期刊：
影响因子：
--
通讯作者：
M. Hennessy;A. Vitale;O. Matar;J. Cabral
中科院分区：
文献类型：
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作者：
M. Hennessy;A. Vitale;O. Matar;J. Cabral
正面光聚合（FPP）是一种多用途定向凝固工艺，通过选择性地将光敏单体浴暴露在光下，可用于快速制造聚合物网络材料。FPP的一个特点是单体到聚合物的转换曲线呈现行波的形式，从照射表面传播到未聚合体。FPP的实际实现需要详细了解这些行波的转换剖面和速度。本理论研究的目的是(i)确定FPP发生的条件，（ii）探索如何利用光衰减和质量传递来精细调整转换剖面和传播动力学。我们的研究结果量化了相对于FPP所需的聚合速率的强光学衰减和缓慢的质量传递。行波的形状主要由整齐和聚合材料的光学衰减系数的大小控制。出乎意料的是，我们发现质量扩散可以增加聚合的净程度，加速固体网络的生长。理论预测与代表性系统的实验数据非常吻合。
Frontal photopolymerization (FPP) is a versatile directional solidification process that can be used to rapidly fabricate polymer network materials by selectively exposing a photosensitive monomer bath to light. A characteristic feature of FPP is that the monomer-to-polymer conversion profiles take on the form of traveling waves that propagate into the unpolymerized bulk from the illuminated surface. Practical implementations of FPP require detailed knowledge about the conversion profile and speed of these traveling waves. The purpose of this theoretical study is to (i) determine the conditions under which FPP occurs and (ii) explore how optical attenuation and mass transport can be used to finely tune the conversion profile and propagation kinetics. Our findings quantify the strong optical attenuation and slow mass transport relative to the rate of polymerization required for FPP. The shape of the traveling wave is primarily controlled by the magnitude of the optical attenuation coefficients of the neat and polymerized material. Unexpectedly, we find that mass diffusion can increase the net extent of polymerization and accelerate the growth of the solid network. The theoretical predictions are found to be in excellent agreement with experimental data acquired for representative systems.